TRADITIONAL POSTER - ismrm

Poster Sessions
2243. Identifying the Ischaemic Penumbra by Probing Tissue Metabolism and Imaging Changes in Tissue
Lactate.
William Matthew Holmes 1 , Maria Rosario Lopez Gonzalez 2 , Lindsay Gallagher 1 , Graeme A. Deuchar 1 , I
M. Macrae 1 , Celestine Santosh 3
1 GEMRIC, Wellcome Surgical Institute, Univeristy of Glasgow, Glasgow, United Kingdom; 2 SINAPSE, Clinical Physics, University
of Glasgow, Glasgow, United Kingdom; 3 Institute of Neurological Sciences, Southern General Hospital, Glasgow, United Kingdom
One of the most important considerations when treating acute stroke patients is to establish whether potentially salvageable (penumbral) tissue is still present
within the brain. Currently perfusion-diffusion mismatch MRI is used, which is an indirect measure lacking precision . Here we propose a new MRI method
for imaging the ischaemic penumbra based on the brain’s capacity to use lactate as a metabolic substrate. Spectroscopic imaging is used to map the changes
in tissue lactate induced by giving a challenge of 100% oxygen.
2244. Estimation of the Onset Time of Cerebral Ischemia in Rats Using T 1ρ MRI
Kimmo T. Jokivarsi 1 , Yrjö Hiltunen 2 , Heidi I. Gröhn 3 , Olli H. Gröhn 1 , Risto A. Kauppinen 4
1 Department of Neurobiology, A.I.Virtanen -Institute, Kuopio, Finland; 2 Department of Environmental Science, University of Kuopio,
Kuopio, Finland; 3 Department of Clinical Physiology, Nuclear Medicine and Neurophysiology, North Karelia Central Hospital,
Joensuu, Finland; 4 Department of Radiology, Dartmouth Medical School, Hanover, NH, United States
MRI parameters can be used to acquire information about stroke and its progression. We investigated the prediction potential of absolute T 1ρ in cerebral
ischemia in a rat stroke model. Our results show that δT 1ρ can give an accurate estimate of ischemia time. Clinically this method provides an easy and fast
MR method for ischemia time estimation that can be used in the absence of a priori knowledge or as an additional confirmation for the clinical estimate of
stroke onset.
2245. Artificial Neural-Network Prediction of Ischemic Tissue Fate in Acute Stroke Imaging
Shiliang Huang 1 , Qiang Shen 1,2 , Timothy Q. Duong 1,2
1 Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States; 2 Department
of Ophthalmology/Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
A flexible artificial neural network (ANN) algorithm was developed and applied to predict ischemic tissue fate on three stroke groups: 30-min, 60-min and
permanent MCAO in rats. CBF, ADC and T2 were acquired during the acute phase up to 3hrs and again at 24hrs followed by histology. Infarct was
predicted pixel-by-pixel using only acute (30-min) stroke data. Receiver-operating-characteristic analysis was used to quantify prediction accuracy. It was
concluded that the ANN predictive model has the potential to serve as promising metrics for diagnosis, prognosis and therapeutic evaluation of acute stroke.
2246. Prolonged Post-Ischemic Hyperperfusion: A Systematic Multimodal MRI Study
Qiang Shen 1,2 , Fang Du 1 , Shiliang Huang 1 , Timothy Q. Duong 1,2
1 Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States;
2 Ophthalmology/Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
Regional hyperperfusion after stroke is a frequent, yet poorly understood, phenomenon. In this study, multimodal MRI (diffusion, perfusion, T2, T1, pHweighted
and dynamic contrast-enhanced imaging, and MRA) were acquired in a 30-min transient MCAO in rat. Significant hyperperfusion was observed
24hrs post-occlusion and peaked at 48hrs. Hyperperfusion areas were consistent with regions with T1 and T2 increases, and early-phase pH decrease, and
late-phase permeability changes. MRA showed significant vasodilatation of distal small arteries. We conclude that hyperperfusion does not appear to salvage
tissue. Multimodality MRI investigation helps to gain significant insights into the underlying physiological changes associated with hyperperfusion.
NRA & CSF Studies with Clinical Applications
Hall B Tuesday 13:30-15:30
2247. Magnetic Resonance Angiography of the Mouse Cerebrovascular System at 17.6 T
Firat Kara 1 , Alia Alia 1
1 Leiden Institude of Chemistry, Leiden University, Leiden, Netherlands
As magnetic field strength increase toward higher fields , it allows significant improvements in MRI techniques by enhancing contrast to noise and signal
to noise ratio. The use of magnetic resonance angiography (MRA) in ultra high magnetic field to visualize cerebrovascular structure of animals, promote
development of early diagnosis and treatment of human neurodegenerative diseases. In this study, an improved contrast-to-noise ratio at 17.6 T imaging
contribute to visualization the smaller vessels of the mouse brain. Branches of anterior cerebral artery (ACA)are better depicted on maximum intensity
projections(MIP) with 17.6 T imaging than MIPs obtained with 9.4.
2248. Time of Flight Magnetic Resonance Angiography of the Canine Brain at 3T and at 7T - A Quantitative
Comparison
Steffen Sammet 1 , Paula Martin-Vaquero 2 , Rita L. Echandi 2 , Ronaldo C. da Costa 2 , Christina L. Tosti 1 ,
Michael V. Knopp 3
1 Department of Radiology, The Ohio State University, Columbus, OH, United States; 2 Veterinary Hospital, The Ohio State
University, Columbus, OH, United States; 3 Department of Radiolgy, The Ohio State University, Columbus, OH, United States
The purpose of this study was to evaluate the ability of 2D ToF-MRA to depict cerebral arteries in the canine brain and to compare the results obtained from
a high field magnet (3T) with an ultrahigh field magnet (7T). ToF-MRA at high and ultra-high magnetic fields should be included in the MRI imaging
protocol of dogs suspected of having cerebrovascular disease. 7T field ToF-MRA allows a better delineation of small vessels in the canine brain than 3T
ToF-MRA.